Electron discharge device



Oct. 1934- v. 1.. RONCI El AL ELECTRON DISCHARGE DEVICE Filed May 18.1932 2 Sheets-Sheet 2 S 2147 R" A BY Walla/164M ATTORNEY Patented Oct.9, 1934 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICEApplication May 18, 1932, Serial No. 612,143

15 Claims.

An object of this invention is to maintain uniform spacing between anincandescible electrode and other electrodes in electron dischargedevices and to prevent setting up deleterious stresses in theincandescible electrode.

In one embodiment of this invention an electron discharge devicecomprises an enclosing vessel consisting of two vitreous end portionshermetically sealed to an intermediate cylindrical metallic portionwhich serves as the anode of the device. A grid assembly is supportedfrom one end portion and a cathode assembly is supported from the otherend portion.

The cathode assembly includes a metallic collar which is sealed to astem and a spider member mounted within the collar and supporting aplate member. Another plate member is supported from the first platemember by a plurality of machine screws which are threaded into theformer plate member and enable adjustment of the spacing of the platemembers. A rigid metallic standard extends through the guide in thespider and is slidable therein. A tension spring encircling an endportion of the standard, is secured to one of the plate members andbears against the end of the standard.

A pair of relatively rigid conductor rods are sealed in the cathodesupporting stem and extend within, but out of contact with thecylindrical collar. A platform is slidably mounted upon the guide forthe standard, adjacent the cylindrical collarand is supported solely bythe conductor rods. Another platform is mounted upon the end of thestandard remote from the cylindrical collar and is substantiallyuniversally rockable with respect to the standard. A multi-sectionfilamentary cathode is suspended between the two platforms andsupportsthe standard. The standard constitutes a gravity actuated or mass memberand produces a tension in the cathode, which may be adjusted by varyingthe spacing between the plate members with a resultant variation in thetension of the spring engaging the standard.

This construction enables expansion and contraction of the filamentarycathode with temperature variations, maintains a uniform tension in theseveral sections of the electrode, and preserves the form of the cathodeand the proper space relation between the cathode and the otherelectrodes of the device.

The invention and the features thereof will be understood more clearlyand fully from the following detailed description, reference being hadto the accompanying drawings in which:

Fig. 1 is an elevational view of an electron discharge deviceillustrative of one embodiment of the invention with portions brokenaway to show details of the cathode and grid assemblies more clearly;

Fig. 2 is an elevational view of the grid assembly of the device shownin Fig. 1, partly in section and partly broken away, to show the gridassembly more clearly;

Fig. 3 is a plan view partly broken away, taken along line 3-3 of Fig.2;

Fig. 4 is an enlarged view in perspective of the cathode assembly of thedevice shown in Fig. 1, partly broken away to show the association ofthe cathode leading-in wires and the cathode more clearly;

Fig. 5 is an exploded view showing the support for the cathode standard;

Fig. 6 is an enlarged detail view of the upper platform of the cathodeassembly;

Fig. '7 is a cross-sectional view along line 7-7 of Fig. 6;

Fig. 8.is an enlarged detail view in cross-section showing the guide andthe bearings for the oathode standard;

Fig. 9 is an enlarged detail view, partly in sec- 35 tion, showing themounting of the lower platform upon the cathode standard; and

Fig. 10 is an enlarged detail view partly broken away and partly insection of the cathode conductor rods.

Referring now to the drawings, an electron discharge device illustrativeof one embodiment of this invention, comprises an enclosing vesselincluding a cylindrical metallic portion 10 which is adapted to serve asthe anode of the device and two vitreous portions 11 and 12 eachhermetically sealed at one end to the metallic portion 10. The vitreousportion 11 is provided with a hollow reentrant stem 13 to the inner endof which a cylindrical metallic sleeve or collar 14 is sealed. Atri-armed metallic spider 15 (shown more clearly in Fig. 5) is securedwithin the sleeve 14 by a plurality of screws 16, and is provided withan axial bore in which a tubular guide member 1'7, which may be ofsteel, is securely fitted. A pair of metallic sleeve inserts 18, whichmay be of molybdenum, are provided at the ends of guide member 17 andform bearings for a slidable elongated rod or standard 19 which extendsaxially of the anode portion 10 and projects beyond the 1-1 end of thespider nearest the stem 13. A metallic plate is secured to one end ofthe spider 15 by a screw 21 and is provided with a centrally disposedaperture 22 through which the guide member 17 extends. Another metallicplate 23 is positioned adjacent the other end of the spider 15 but outof contact therewith and is supported solely by machine screws 24 whichare threaded into the plate 23, and extend slidably through the rigidplate 20. The screws 24 may be locked relative to each other by a cotterwire 25. A helical spring 26 encircles the standard or rod 19 and isseated upon the plate 23. One end of the spring 26 is secured to theplate member 23 and the other end of the spring is seated on a cap 27which is seated upon an insulating collar 28. The collar 28 is seated,together with an interposed washer 29, upon a shoulder 30 of thestandard 19.

The stem 13 is provided intermediate its ends with an internal vitreousflange 31 which carries a pair of outwardly directed vitreoustubulations 32. Metallic sleeves 33, such as copper, are hermeticallysealed to one end of the tubulations 32 and have secured thereinmetallic rods forming leading-in conductors for the cathode of thedevice.

As shown more clearly in Fig. 10, the conductor rods include a coppersection 34 which is secured within the sleeves 33, having a bore intowhich a reduced end portion 35 of a molybdenum section 36 extends. Thesections 34 and 36 are preferably are welded together, a nickel weldingsleeve 37 being interposed between the reduced end portion 35 of themolybdenum section 36 and the copper section 34. The conductor rods maybe connected to an appropriatesource of current by stranded conductors38 secured to the metallic sleeves 33.

The metallic rod sections 36 extend between the arms of the spider 15and out of contact with the spider and the sleeve 14. Each of the rodsections 36 is formed with a short threaded portion 39 and an elongatedlinear portion 40 extending lengthwise of the enclosing vessel andwithin the anode portion 10. The threaded portions 39 extend throughopposed flanged insulators 41 positioned in apertures in a metallicplatform 42, and each portion has mounted thereon a metallic nut 43which clamps the insulators 41 against a shoulder 44 on the rod section36 and thereby secures the platform 42 in position. A plurality of rods45 extend through flanged insulators 46 in the platform 42 and havesecured thereto, as by welding, metallic buttons 47 which look theinsulators in position. The rods 45, which may be of molybdenum, areprovided with bent portions 48 which are secured to the rod sections 36.In the particular embodiment shown there are four rods 45, two of therods beingsecured to one of the rods 36 and two to the other of the rods36, as shown in Fig. 7, so that three conductors of positive polarityand three of negative polarity are provided. The rods-45 and 40 and rods34, 36 and the platform 42, in the specific construction shown aretherefore rigidly interconnected and form a unitary assembly supportedfrom the stem 13. The platform 42 is slidably mounted upon the guidemember 17 adjacent the lower end thereof. A triarmed platform or. spider49, which may be of molybdenum, is mounted upon a reduced headedextension 50 of the standard 19, as shown more clearly in Fig. 9, and isuniversally rockable with respect to the standard 19.

A filamentary cathode consisting of a plurality of V-shaped sections 51,which may be of tungsten, is suspended between the platforms 42 and 49and is arranged within a substantially cylindrical boundaryconcentrically within the anode portion 10 of the enclosing vessel. TheV-shaped sections of the cathode are threaded through bores 52 in thearms of the platform 49 and the ends of the sections are disposed inslots 53 in the rods 40 and 45. The ends of the cathode sections aresecured in the slots by tightly wound wire helices 54, which may be arewelded to the ends of the cathode sections 51 and the rods 40 and 45. Inview of the connections shown in Fig. '7, it will be apparent that thesections of the cathodes are electrically in parallel.

The normal position of the cathode structure is as shown in Fig. 4. Thestandard 19 which is freely slidable in guide member 17, constitutes agravity actuated or mass member, the mass of which acts along the lengthof the cathode and thereby produces a tension in the filamentarysections 51 of the cathode. The degree of the tension may be adjusted byvarying the separation of the plates 20 and 23, thereby varying thetension of the helical spring 26. During the operation of the device theexpansion and contraction of the leading-in conductor rods 34, 36 areaccompanied by movement of the platform 42 along the guide 17 so that nobuckling or deleterious stresses in the rods are produced. The expansionand contraction of the filamentary sections 51 of the cathode arecompensated by the helical spring 26 acting upon the standard 19. Anunequal expansion of the sections 51 is compensated by the rockingmovement of the spider or platform 49. This construction, therefore,maintains a substantially uniform and constant tension in the sections51 and preserves the form of the cathode as a whole so that the spacingof the cathode with respect to the anode is substantially uniform andthe electrical characteristics of the device are maintainedsubstantially constant. Moreover since the setting-up of deleteriousstresses in the cathode structure are prevented, the operating life ofthe device is materially extended.

In order to prevent arcing discharges between the anode and therelatively sharp edges on portions of the cathode supporting structure,a shield is provided about the assembly adjacent the stem 13. Thisshield comprises a cylindrical supporting band 55 which is secured tothe sleeve 14 by screws 56, and a frusto-conical perforated or wire meshportion 57 which extends between the band 55 and the platform 42 andmakes sliding contact with the platform. A cylindrical shield 58 whichmay be of a good heat conducting material, such as nickel, extends fromthe anode portion 10. The shield 58 decreases the potential gradientbetween the anode and the portions of the filament assembly adjacent thestem 13 and also protects the seal between the anode 10 and the vitreousend portion 11 by reflecting heat away therefrom.

The opposite end portion 12 of the enclosing vessel is formed with areentrant stem 59 having an outwardly extending neck portion 60. Ametallic cap 61 which may be of copper is hermetically sealed to theneck portion 60 and extends outwardly beyond the end of the portion 12to form an external terminal for the grid of the device. The gridassembly, as shown more clearly in Fig. 2,.qomprises a cylindricalsupport 62, preferably of copper, which may be secured within the cap 61as shown and described in a Patent ing.

No. 1,907,123 granted May 2, 1933, of Victor L. Ronci. A metallic collar63 encircles the inner end of the support 62 and is secured to thesupport by a plurality of screws 64. The collar is provided withcounter-sunk portions adjacent the heads of the screws 64; so that thematerial of the support may be forced into the counter-sunk portions,and the collar and support securely locked with respect to each other. Aplurality of apertures 65 are provided in the collar, one in axialalignment with each of the screws 64 to allow the insertion of ascrew-driver for fixing or removing the screws. The collar 63 is alsoprovided with a plurality of equally spaced bores parallel to the axisthereof into which rigid parallel uprights 66, such as of molybdenum,extend. The uprights 66 may be secured to the collar by welding as shownat 67, and extend parallel to the axis of the anode portion 10. Ahelical wire control electrode or grid 68, which may be of molybdenum,is carried by the uprights 66, each convolution of the control electrodeor grid being spot welded to each of the uprights. This cons'tructionprovides a rigid structure which will not distort during the operationof the device.

The convolutions 69 at. the end of the grid remote from the support 62are preferably spaced less than the remaining convolutions of the gridin order to appreciably block electrons and to thereby confine the anodespace current. The collar 63 is preferably enclosed in a shield '70,which-may be of nickel, to prevent deleterious heating of the support62. A cylindrical shield '11 of a metal having good radiatingproperties, for example, nickel, extends from the anode l0 and protectsthe seal between the anode and the vitreous end portion 12, and reducesthe potential gradient between the control electrode or grid and the endof the anode.

In order to prevent excessive heating of the anode 10 during theoperation of the device, a cooling jacket is provided comprising ametallic casing 72 concentrically disposed about the anode 10 andsecured thereto at opposite ends, by braz- The jacket is provided withan inlet 73 at one end of the casing, and an outlet 74 at the other endof the casing. The construction and features of the cooling jacket aredescribed in greater detail in a copending application of Victor L.Ronci, James E. Clark, and Douglas A. Hale, Serial No. 612,144 filed May18, 1932.

Although the invention has been described in detail with reference to aspecific embodiment in high power electron discharge devices, it is tobe understood, of course, that modifications may be made in the specificstructure shown without departing from the spirit and scope of thisinvention as defined in the appended claims.

What is claimed is:

1. An electrode assembly comprising a support, a standard extendingthrough said support and slidable therein, a filamentary electrodehaving portions fixed with respect to said support and supporting saidstandard, and an adjustable resilient connection joining said standardand said support.

2. An electrode assembly-comprising a support, a standard extendingthrough said support and slidable therein, a filamentary electrodehaving one end fixed with respect to said support and connected to saidstandard remote from said support, said electrode supporting saidstandard and being tensioned thereby, and a helical tension springcoupled to said support and said standard.

3. An electrode assembly comprising a support,

a standard extending through said support and slidable therein, afilamentary electrode coupled to said support and connected to saidstandard remote from said support, said electrode supporting saidstandard and tensioned thereby, a tension spring secured to said supportand engaging said standard, and means for adjusting the tension of saidspring.

4. An electrode assembly comprising a support, a standard extending fromsaid support, a platform slidably disposed about said standardintermediate the ends thereof, a second platform mounted on saidstandard adjacent one end thereof and universally rockable with respectto said standard, and a filamentary electrode extending between andcoupled to said platforms.

5. An electrode assembly comprising a stem, 9. support mounted on saidstem, a standard extending from said support, leading-in conductorsextending through said stem, a platform supported by said conductorsloosely surrounding said standard, a second platform mounted on saidstandard and universally rockable with respect thereto, and afilamentary cathode coupled to and extending between said platforms.

6. An electrode assembly comprising a stem,

leading-in conductors extending through said stem, a platform supportedby said conductors, a filamentary electrode coupled to said platform,gravity actuated means for tensioning said filamentary electrode, andmeans for adjusting said gravity actuated means.

'7. An electrode assembly comprising a stem, leading-in conductorsextending from said stem, a platform supported by said'conductors, afilamentary electrode coupled to said platform, gravity actuated meansfor tensioning said filamentary electrode, and means regulating thetensional force of said standard during expansion and contraction of thefilamentary electrode.

8. An electrode assembly comprising a stem, a support mounted on saidstem, leading-in conductors extending through said stem, a platformsupported by said leading-in conductors, a filamentary electrode coupledto said platform, and 120 a standard extending through said platform andsupport and slidable therein, said standard being connected to saidfilamentary electrode and supported thereby.

9. An electrode assembly comprising a stem, 9. support mounted on saidstem, leading-in conductors extending through said stem, a platformsupported by said leading-in conductors, a filamentary electrode coupledto said platform, a mass member extending from said support and guided 1thereby, said mass member being supported by said electrode and applyingtension to said electrode, resilient means between said mass member andsaid support, and means for varying the tension of said resilient meanswhereby the tension in said electrode is adjusted.

10. An electrode assembly comprising a stem, a support mounted on saidstem, a pair of plate members carried by said support, a filamentaryelectrode coupled to said support, a rod member supported by saidelectrode and extending through said support and plate members, fortensioning said electrode, a spring member secured to one of said platemembers and engaging said rod, said spring member acting to hold saidrod 1 against said electrode, and means for varying the spacing betweensaid plate members whereby the tension in said spring member and saidelectrode is adjusted.

11. An electrode assembly comprising a stem, a 180 members adjacent saidsupport, one of said plate members being secured to said support, means6 adjustable in length supporting the other plate member from said oneplate member, leading-in conductors extending from said stem, a platformadjacent said support carried by said conductors, a filamentaryelectrode coupled to said platform, a rod member supported by saidelectrode and extending through said guide member and platiorm and ahelical spring secured to said other plate member and engaging said rodmember, the tension in said spring being variable by said adjustablemeans to adjust the tension in said filamentary electrode.

12. An electron discharge device comprising an enclosing vesselincluding a cylindrical metallic portion serving as an anode, vitreousportions sealed to opposite ends 01' said metallic portion, eachot saidvitreous portions having a reentrant stem, a grid electrode supportedfrom one of said stems and concentrically disposed within said anode, asupport mounted on the other reentrant stem, a cathode coupled to saidsupport including a plurality of V-shaped sections lying in acylindrical boundary concentrically within said grid electrode andanode, means including a gravity actuated member for tensioning saidsections simultaneously, said means being variable to compensate forexpansion and contraction of said sections, and additional means forcompensating for unequal expansion in said sections to maintain thecylindrical form of said cathode.

13. An electron discharge device comprising an enclosing vessel having areentrant stem, at standard extending from said stem, leading-inconductors adjacent said standard and extending through said stem, aplatform slidably encircling said standard and carried by saidleading-in conductors, a filamentary electrode coupled to said platform,an anode encircling said electrode, and a hollow shield encircling saidstandard and said conductors, said shield being secured to said stem atone end and slidably contacting with said platform at the other end.

14. An electrode assembly comprising a stem, a collar mounted on saidstem, a support'mounted within said collar, a guide member within saidsupport, a plurality oi. spaced bearing sleeves in said guide member, astandard extending through said guide member and slidable on saidbearing sleeves, a resilient connection between said standard and saidsupport, a rockable spider member mounted on said standard, a platformslidably mounted on said standard remote from said spider member, and afilamentary electrode coupled to said platform and said spider member.

15. An electron discharge devicecomprising an enclosing vessel having astem, a metallic support extending from said stem, a collar encirclingsaid support and carried thereby, a plurality of rods supported by saidcollar, a helical grid carried by said rods, a cathode within saidhelical electrode, an anode encircling said helical electrode, and aheat radiating shield mounted upon said collar, having a portiondisposed between said cathode and said collar.

